Our blood carries so much all over our body. It is truly a reflection of how well or how badly we are doing. Doctors everywhere rely so much on this reflection to help understand and diagnose disease processes. As pathologists, reading this reflection is one of the more challenging tasks. It is a bit like detective work, isn’t it? Three types of blood cells, so to speak, yet between them they carry a true measure of the state of the body.
If you know how to accurately interpret a blood film, you can tell their sex and geography, if they smoke or are an alcoholic, if they are experiencing malabsorption or are carrying an extra 21st chromosome. An astute pathologist knows the true far-reaching potential of a blood smear, and it is imperative for a trainee in the field of Pathology to develop the right approach to interpretation of a blood report. And more importantly, it is imperative to know how to convey the information in the right and relevant manner to the patient and the consulting physician.
Writing a blood smear report is much like telling a story. We set the scene, we introduce the characters and then follow them through their trials and tribulations. Sometimes, there is a sole protagonist, so we focus on him; sometimes everyone is the story.
Let us begin ours.
A peripheral blood smear has just been handed to you. You ask for the complete blood count report and, for any relevant history and clinical findings for the patient. You check whether it has been stained properly- not too pink, not too purple- just the right hue.
You see it under a low magnification to get a sense of where you are, just like a drone footage of the first scene of your story. You find the right spot for further examination- not too thick, not too thin- somewhere between the tail and the body. You do not want too much of a crowd, our characters can get lost. Once you decide on the perfect Goldilocks spot, you zoom in.
You, the author, have just set the scene.
Now we meet the characters. Every character has a backstory, where they came from right up to when we meet them. To properly understand the length and depth and width of their character we need to elaborate on their two aspects- a quantitative one, and a qualitative one. In blood, there are three main characters- red blood cells, white blood cells and platelets, and each one deserves their quantitative and qualitative description.
First up, the red blood cells. Erythrocytes. Without them, our tissues would starve for oxygen and die. Without them, we would lose all pink colour- from our mucus membranes and peripheral smears. Let us begin with their quantitative description- how many are they, and how are they arranged.
Now let us describe them qualitatively. What is their size, their shape, their colour? Remember, variety is the spice of life- sprinkle it! Mention the poikilocytes (differently shaped RBCs) seen. And if everything looks so varied that you see different shapes and sizes- that’s anisopoikilocytosis for you!
All of this was an external description but let us really get into the heart of these characters. Look inside, literally. See if there are any inclusions in the RBCs.
Now, let us move on from the reds to the whites. Leucocytes. These cells are the army, both defensive and offensive. This army has five units- neutrophils, lymphocytes, monocytes, eosinophils, and basophils-each with their own targets but also the capacity to team up in case something is wrong. The genre of your story has just become “action”- with violence, and a lot of collateral damage. First, quantity. Are the cells more? If yes, which kind is more? Each one in abundance has a different story.
Where there’s fighting, there is good vs evil. Look closely to make out if all in the army look like heroes or some villains have crept in. Identify and describe any atypical forms, if present. Look closely at the nuclei and cytoplasm separately and see if anything looks different.
Your story is really taking shape, isn’t it? From the passionate red cells to the combative white cells, let us now turn our attention to the quiescent platelets. Underrated but oh so vital! Take in their number, see how they are distributed, before moving to describing their size and colour.
Let us shake up the genre once more and look for aliens! There might be something lingering, swirling or just sitting in the peripheral smear that should not be there. Yes, you are right. I am talking about hemoparasites. Look both inside and outside cells. Go back to the drone footage again, see if something pops up. Look between cells and in them, especially red blood cells- passion attracts trouble, does not it!
Once you have written all your relevant findings, now summarize them. Who do you think was the main character? Or is it an ensemble cast? Is it just anemia, or anemia with leukemia? Is it just thrombocytopenia, or a possible microangiopathic hemolytic anemia lurking too?
Let the reader (patient and the consulting clinician) know what to expect from this story.
Congratulations, you are now a storyteller.
- Wintrobe’s Atlas of Clinical Hematology, Second Edition
- A Beginner’s Guide to Blood Cells by Barbara Bain, Third Edition
- Dacie and Lewis Practical Hematology, Twelfth Edition
Written and doodled by:
Dr. Deeksha Sikri
MBBS, DNB (Pathology)
Department of Pathology
St. George’s University
Grenada, West Indies
Creator of Pathodoodles
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